The Bosnian genocide suspect Radovan Karadzic will conduct his own defence in his war crimes tribunal at The Hague and is convinced he will be cleared of the charges, his lawyer said today.

Karadzic, who was arrested after spending 12 years on the run, has been allowed to shave and have a haircut to get rid of the heavy disguise that enabled him to live and work freely in the Serbian capital, Belgrade.

Karadzic now looks "exactly the same as 14 years ago, only older," said his lawyer, Sveta Vujacic.

Further details about Karadzic's life in hiding emerged today, including that he had a girlfriend, claimed his grandchildren lived in the US and was a regular at his local bar.

The leader of the Bosnian Serbs in the 1992-95 Bosnia war could be handed over to authorities in The Hague as early as this weekend, a Serbian official said.

Karadzic, who masterminded the three-year siege of Sarajevo and is held responsible for the massacre of 8,000 Bosnian Muslims in Srebrenica, is not expected to win his appeal against extradition to the Netherlands.

Karadzic, who is being held in a Belgrade prison, was in good mental and physical condition, Vujacic said. He was not talking to investigators but "defending himself with silence".

"He is going to have a legal team in Serbia but he will be defending himself [without a lawyer] during his trial at The Hague," Vujacic told Reuters. "He is convinced that with the help of God he will win."

Serbian authorities said Karadzic was arrested on Monday, though his lawyer says he was detained last Friday.

He was one of three war crimes fugitives from the Yugoslav wars whose arrest was a key condition for Serbia to move towards European Union membership.

More details emerged of Karadzic's life on the run, during at least part of which he practised alternative medicine.

Over the past year, he lived in a flat in New Belgrade, a suburb of the city. He held lectures as an expert on meditation and health at seminars around the country, the Serbian daily Blic reported.

The paper said he had a girlfriend, a "mysterious, attractive" dark-haired, middle-aged woman he introduced as Mila, "the love of his life". She was reportedly by his side at all times.

"She escorted him to every lecture and behaved like his wife. They held hands ... when we would travel, and there would be no room in the car for her. He [Karadzic] would say he is not going without her," Tanja Jovanovic, one of the staff at Zdrav zivot [Healthy Life] magazine, to which Karadzic contributed articles, told Blic.

Other staff at the magazine described Karadzic - who went by the name of Dragan David Dabic - as a charismatic, nice man with a peculiar style of dress, resembling an Indian guru.

At lectures, he was introduced as a neuropsychiatrist who had travelled the world.

Zoran Pavlovic, who was hired by Karadzic to set up a website for his clinic, said he had visited Karadzic's flat in New Belgrade and seen a framed photograph of four boys - all dressed in yellow LA Lakers T-shirts - who Karadzic said were his grandsons, living in the US.

Misko Kovijanic, who owns a bar in Karadzic's neighbourhood, said Karadzic was a regular who liked to sip red wine in the tavern, which is decorated with photos of Karadzic and his fellow war crimes fugitive Ratko Maldic.

"I'm very proud that he came to my pub, and I'm very sad that he was arrested," Kovijanic said.

The former Serbian prime minister, Vojislav Kostunica, whose government was accused of failing to act against Karadzic, today criticised his arrest. Kostunica, a nationalist who criticised the international recognition of Kosovo, was voted out of power in May elections.

Last night, dozens of nationalists took to the streets in Belgrade, clashing with police. Chanting "Treason!" the demonstrators threw stones and clay pots at riot police. Five demonstrators and a policeman were injured.

Gordon Brown labelled Karadzic as "someone who violated human rights in his own country" and said the British government was behind the efforts to bring him before The Hague.

"I hope now that the success that has been achieved in capturing the prisoner we can proceed to the ... court being able to go about its work of trying the person they have indicted," he said.

Karadzic has twice been indicted for genocide, for the massacre in Srebrenica in 1995 and for the 43-month siege of Sarajevo. Some 11,000 people died in the city from sniper fire, mortar attacks, starvation and illness.

Karadzic had wanted Serb areas of Bosnia to be linked to Serbia and other areas dominated by Serbs at a time when Slobodan Milosevic, the then Serbian president, was fanning nationalism in Serbia.

Most Serbs see the Hague tribunal as biased against their nation, and as having an agenda to give them the lion's share of the blame for the 1992-95 conflict.

"He had planned to turn himself in January 2009 because that is when the Hague tribunal is due to stop launching new trials," his brother Luka Karadzic said.

"It would be more fair if he could be tried in Serbia with the presence of an international judge."

The EU has called the arrest "a milestone" on Serbia's road to joining the EU but said Belgrade must go further to reap the full benefits, by arresting Karadzic's former military chief Ratko Mladic, who is wanted on the same charges.